you're trying to protect your device from the environment. that's generally where they've been used. colombia, thailand, maybe even in pakistan. so it is kind of odd that they would use that here in a domestic setting. but, again, they don't know -- they don't have any suspect at all. >> it's also important to point out that this is an investigation where all of the resources and intelligence community are being used and they will have a backlog of intelligence they have to go through, intercept, satellite intelligence, signal intelligence, which they can monitor all of this stuff in realtime. >> they can't. and from what they monitor on a daily basis, minute-by-minute basis, from known suspects around the world, they had zero indication from this event. now you go back based on what happened and what you do know, you check cell phone towers and those international conversations and run your traffic through suspicious groups around the world. just speaking to the boston law enforcement source, a federal source earlier today, and a sense of is